I still have much to add to the Mustang III Performance thread but I thought for a small change I would throw what I have on the Do 335 out there. And as I have said before, I am not an authority on German fighter aircraft. So If anyone has any other "Official documentation" or other information on this German fighter, please do not hesitate to post it. Any information will be very welcomed.

From www.aeroflight.co.uk:

"Plagued by mechanical unreliability and lack of aviation fuel, the operational career of the Do 335 is rather obscure. Do 335A-0 and A-1 aircraft are thought to have flown a number of operational missions with EK335. Some were also used by III/KG2 in the spring of 1945. French fighter ace Pierre Clostermann's book 'The Big Show' mentions an encounter with a Do 335 in April 1945, during which the German aircraft easily outpaced the pursuing Hawker Tempests and escaped. Such events were very rare, so it seems likely that most operations were high speed interdiction missions - many taking place at night."
Engine according to www.aeroflight.co.uk: 2 x DB 603E-1, 1,800 hp. each.

From www.century-of-flight.net:

"By late autumn in 1944, the Do 335A-1 full production model appeared at Oberpfaffenhofen, this introducing the definitive 1,800 hp. 12-cylinder DB 603E-1 engine and two underwing hardpoints capable of carrying fuel or 550 lbs. bombs."
"As far as is known, the Pfeil never entered into combat, although US pilots reported seeing the strange aircraft in the sky during sorties over Germany, and the Erprobungskommmando (EK335?) was forced to send aircraft into a sky which could not be guananteed as being free of hostile aircraft."
Engine according to www.century-of-flight.net: 2 x DB 603A-2, 1,750 hp. each.

The following speed data is taken from a German graph. All the curves might be estimated/calculated except for possibly one. I'll start with the possibly calculated data. The first set of speed figures are for the Do 335A-0 with the DB 603A. The second set is for the Do 335A-1 with the DB 603E-1 and the last set of figures is for the proposed Do 335B with the DB 603 LA engine. Altitude is in meters and speed is in mph:

The last set of figures are marked (DB 603 E mit neuer Leistung noch DB - Angaben von Nov. 1944). My German absolutely stinks. The best I can make out of this is "DB 603 E with new performance according to DB - Angaben von Nov. 1944". There, that is my best attempt.

I was able to come up with another document dated 5/31/44. It is in poor condition and would be very hard to impossible to read if I could read German. The heading appears to be DAUBESCHREIBUNG.? I is a report on the Do.335B-0/B-2. The graph is dated 5/10/44. To me this seems a little early for the testing of this model. I might be estimated/calculated data. I just don't know.

What I can make out goes like this (remember the entire report is blurry including the graphs):

The first set of speed figures are for the Do 335A-0 with the DB 603A. The second set is for the Do 335A-1 with the DB 603E-1 and the last set of figures is for the proposed Do 335B with the DB 603 LA engine.

I believe the DB603LA is the same as the DB603A, except configured for extension shaft drive.

So the Do 335 would have had one DB603A and one DB603LA.

Not sure if any were actually fitted with the E. I will have to check later.

"As the war situation continued to deteriorate, development effort switched from the A-series fighter-bomber to the more heavily armed B-series heavy fighter. Only two B-series prototypes were actually completed and flown - further developments were still under construction, some with two-stage supercharger DB603LA engines capable of 2,100 hp.